新疆喀什地区一次强沙尘天与的成因分析

利用常规气象观测资料、自动站观测资料及数值预报物理量场．对2013年4月16-18日发生在喀什地区的一次强沙尘天气的成因进行分析。结果表明．造成此次天气的主要原因是：受乌拉尔山高压脊控制，强冷空气翻越帕米尔高原．由于喀什地区特殊的地理环境为此次强沙尘天气过程提供了丰富的沙源．造成该地区的强沙天气：前期喀什大部分地区降水稀少、气温偏高，土质疏松。为沙尘天气的加强提供了有利的物质条件和热力条件：地面热低压发展旺盛．形成北高南低的气压场形势．气压梯度增大，低空急流加强，为沙尘天气的发生提供了动力条件。     

地下槽通风降温效果试验

该试验主要是对新建２１ｍ大跨度的高堆粮仓，借助地下槽配备小功率轴流风机，利用冬季低冷天气，进行通风降温，目的在于验证其通风效果。结果表明：降温效果明显，使用方便，节省费用，宜推广应用。     

2016年1月22－26日影响海南岛一次强寒冷天气过程分析

为了深入了解强冷空气影响下海南岛的天气变化特征，进一步提高对强冷空气影响过程预报准确率，利用海南省区域自动站资料、常规天气观测资料以及NCEP/NCAR 2.5°×2.5°一日四次再分析资料，采用天气学原理和动力学诊断分析方法，对2016年1月22—26日影响海南岛一次强冷天气过程进行分析和总结。结果表明，此次强冷天气过程是由于极地涡旋分裂南下，同时乌拉尔山高压脊强烈发展使冷空气在横槽聚集，横槽前部等高线阶梯形势明显，并伴有明显负变高和冷平流，从而有利横槽转竖南压引导强冷空气向南爆发。强冷平流是造成海南岛出现强烈降温的主要原因；另外，由于低纬地区短波槽活跃，短波槽前暖湿气流与南下冷空气共同作用造成降水。     

低温密闭技术在高大平房仓中的应用

在冬季选择气温低，大气湿度小的天气，对高大平房仓的粮堆通过地槽通风系统进行通风降温，效果理想，在春季利用塑料膜密闭门、窗和粮面，使粮温常年低于15℃，从而有效地抑制虫、霉的孳生，延缓粮食陈化，保持品质，实现低温储粮的目的。     

1998年聊城市小麦赤霉病发生特点及防治前景

1998年聊城市赤霉病普遍发生，阴雨天气尤其是扬花期高温高湿是主要因素。目前还没有免疫品种，但调整播期和选用避病品种可大大减轻危害。抽穗至盛花期用80％多菌灵微粉剂低量喷雾对小麦赤霉病防治效果好。     

山地农业的春季冻害和倒春寒防御

利用气象中尺度自动站资料和灾情信息,将丽水市农业生产分为平原地区、低海拔山区、中高海拔山区3种类型,结合山地特点,对2010年两次倒春寒的天气特点进行对比分析。结果表明：（1）倒春寒对农业危害非常大,两次倒春寒的受灾机制和受灾强度不同,不同海拔地区的气象要素和受灾情况的差异性也很大,3月春季低温对平原地区的影响与4月倒春寒天气过程对中高海拔山区的影响基本相当,且明显弱于其低海拔、中高海拔地区的影响;（2）倒春寒天气发生前开展有针对性服务和预防准备以及开展规模化的大棚种植等措施,对提高山地农业倒春寒及春季低温冰冻天气的防御能力意义重大。     

车排子垦区一次冰雹天气雷达回波的特征分析

兵团第七师车排子垦区由于受特殊地理环境的影响,是奎屯河流域易生成雹暴天气的重点区域,特别是离散性、局部性雹暴天气出现较为频繁.本文利用2011年6月22日发生在车排子垦区一次受低涡分裂短波扰动影响的雹暴天气雷达回波资料,对此次雹暴的发生、发展及演变特征进行了研究分析.     

不同播期两系杂交稻穗期耐寒性鉴定及对产量影响研究初报

通过分期播种，对4个两系杂交稻组合在自然低温条件下进行穗期耐寒性鉴定，同时研究不同播种期对两系杂交稻生育特性及产量的影响。结果表明，在穗期遇上连续3d以上低于23℃的低温天气，4个两系杂交稻组合与对照汕优63结实率开始下降，但仍均达75．0％以上；穗期遇上连续3d以上低于20℃的低温天气，则影响较大，各参试组合穗抽不起来或结实率极低。不同播期处理对两优培九、金两优36的生育特性有一定影响，对5个参试组合的产量性状都有较大影响，播种愈迟，产量愈低。     

新疆巴州南部一次沙尘暴天气的成因分析

利用常规micaps资料、自动站观测资料,对2016年4月30日至5月1日出现在巴州南部的一次沙尘暴天气的成因进行了分析,结果表明,造成此次沙尘暴天气的主要原因是由于西西伯利亚低槽发展,地面冷锋东移南下,南疆盆地东部热低压共同影响造成。由于巴州平原南部的特殊地理环境为此次强沙尘天气过程提供了丰富的沙源;前期巴州大部气温偏高,降水明显偏少,地面植被稀少、土质疏松,为沙尘天气的加强提供了有利的物质条件和热力条件;南疆盆地热低压发展旺盛,形成西北高东南低的气压场形势,气压梯度迅速增大,低空偏东急流加强,为沙尘暴的发生提供了动力条件。     

柳州强对流天气的气候特征及环流背景分析

为了解柳州市强对流天气的气候特征及其发生的大气环流背景,提高强对流天气的预报准确率和防灾减灾服务,利用广西柳州市各气象观测站1951年以来的常规观测资料以及2005年以来的中尺度自动气象站资料,运用统计分析方法,对柳州市强对流天气的类型和气候特征进行分析。结果发现：柳州市的强对流天气主要有冰雹、雷雨大风和短历时强降水3类,冰雹主要发生在2—4月,其年代际变化呈单峰型,1970—1990年为冰雹高发期;雷雨大风年代际变化呈线性减少趋势,平均每10年约减少18.9次,1990年以前较多,1990年以后迅速减少;短历时强降水主要发生在汛期的4—9月,其年际变化趋势不明显。在统计分析的基础上,选取典型个例,利用NCEP再分析资料,分析各类强对流天气的环流形势特征,结果表明：冰雹发生前广西200hPa处于槽前西南急流中,500hPa处于槽前,850hPa贵州境内有低涡切变,柳州处于低涡东南部和西南急流左侧强烈辐合区中,地面一般有强烈的暖低压或低压倒槽发展;短历时强降水发生前广西地面一般处于锋前暖区中,多为暖区暴雨;雷雨大风则主要有副高边缘型、低槽冷锋型和低槽+副高边缘型3类。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.